A conventional radiographic apparatus has a radiation grid for removing scattered radiation in order to prevent scattered radiation from an inspection object from impinging on a flat panel radiation detector (radiation detecting device). The radiation grid is formed of an alternate arrangement of grid foil strips which absorb the scattered radiation and interspacers which transmit the radiation. The grid foil strips are formed of a material such as lead which absorbs radiation, typically X-rays. The interspacers are formed of an intermediate material such as aluminum or an organic material which transmits radiation, typically X-rays. However, when the radiation passes through the interspacers, the radiation (direct radiation) other than the scattered radiation will also be absorbed by the intermediate material. So an air grid, in which the interspacers are made voids for reliably transmitting the radiation (direct radiation) other than the scattered radiation, has been used as radiation grid in recent years.
Incidentally, in portions where the direct radiation is blocked by the grid foil strips, foil shadows due to the grid foil strips appear in radiological images. So, Applicant herein has proposed false image removing methods for removing false images resulting from the foil shadows (see Patent Documents 1 and 2, for example).